Guard means for electric switches



Aug. 15, 1939. F. G. VON HOORN GUARD MEANS FOR ELECTRIC SWITCHES Filed Feb. 12, 1937 Tnve ntoT": Fred G .VOTW HOoTn,

r w m HS Attorney.

Patented Aug. 15, 1939 UNITED STATES PATENT OFFICE 2,169,860 I cum MEANS roa memo swrrcnr:

New York Application February 12, 1937, Serial No. 125,406

4 Claims.

My invention relates to guard means for elec-' tric switches or circuit breakers, more particularly to means for protecting electric switches or circuit breakers against accidental or unauthorized operation and has for an object the provision of simple and inexpensive means of this character.

Electric switches and circuit breakers are often mounted in receptacles or housings with the operating handle or lever of the switch projecting through the cover of the housing which serves as a face plate for the switch. Such housings or face plates have heretofore been provided with channel-like guards for theoperating lever, the sides of the guard being provided with apertures for receiving looking or sealing means such as padlocks for preventing unauthorized or accidental operation of the switch lever. Something is yet to be desired, however, in guard means of this character because of the wide variety of uses to which such enclosed switches are applied.

For example, it may be desirable in some cases to guard the switch against accidental or inadvertent operation while at the same time, providingior emergency operation independently oi the seal or padlock. In other cases, such for example as in public or semi-public buildings, it may be desirable to render the switch completely tamper-proof and inaccessible for operation except upon the "removal of the padlock or seal. It is accordingly a further objectof my invention to provide-simple and reliable. guardmeans of this character capable of ailording apredetermined degree 01' protection, depending upon the character of the switch installation.

In carrying out my invention in one form, I provide a channel-like guard member which is substantially U-shaped in cross-section and comprises parallel side walls connected together adiacent their respective opposite ends byispaced apart yoke members. Detachable means, such for example as screws threadedly engaging the yoke members and the face plate on the electric 7 switch, are provided for securing the'guardmemher to the face plate so that the-operating lever of the switch extends into the space between the yoke members, the side walls extending outwardly from the lace plate substantially parallel to the path of movement of the switch operating lever. These side walls are provided with suitable apertures for supporting a locking bar or bolt in the path of movement of the operating lever, the locking barbeing retained by a suitable padlock or seal.

Thus, the operating lever is protected agains (CI. IO-203) accidental or inadvertent operation, while the threaded detachable means permit ready removal of the channel-like guard member to provide for emergency operation of the switch.

In addition, I provide a hood-shaped cover for the guard member which completely houses the guard member when in its closed position, so that the detachable means are inaccessible. The

side walls 01 this cover member are provided with apertures for receiving the locking bar or bolt so that when the cover member and the looking barare assembled and locked by means of a padlock or seal, the switch lever is inaccessible for operation except upon removal or destruction of the padlock or seal.

For a more complete understanding of my invention, reference may now be had tothe drawing in which Fig. 1 is a perspective view of an enclosed electric switch provided with guard means embodying my invention; Fig. 2 is an elevational view of the switch shown in Fig. 1 with the cover or hood applied to the guard means; and Fig. 3 is a detail perspective view of the cover or hood, together with the cooperating hinge plate for mounting the cover..

Referringnow to the drawing, I have-shown.

my invention as applied to a combined manual tending inwardly from the walls oi the casing H. I

As shown, the walls of the casing H are provided withsuitable-knockouts for permitting wiring of the circuit'breaker. a

The circuit breaker ID, as more fully described in my above referred to applicatiomis provided with a shoulder'portion surrounding the pivoted operating lever or handle it. When the ,circuit breaker is supported on the brackets H,

as shown, this shoulder portion is and the operating lever i6 extend through a suitable aperture in the face plate i2.

, In order to protect the operating lever i6 against accidental or inadvertent operation, I

provide a channel-like guard member which comprises a pair of substantially parallel side walls H which are connected together adjacent their respective opposite ends by spaced yoke members l8, the guard member thus being substantially U-shaped in cross-section. Suitable screws l8 which extend throughthe yoke members l8, the face plate [2, and the supporting member l3, as shown best in Fig. 2, detachably secure the guard member to the face plate l2 with the yoke members i8 and the face plate l2 in iace-to-face relation' and with the operating lever l6, extending through the space between the yoke members so that the side walls i1 extend substantially parallel to the path of movement of the operating lever.

As shown, each of the side walls I! is provided with an aperture 20 arranged to receive a locking bolt or bar 2! which extends across the guard member in the path of movement of the operating lever it, one extending end of the bar 2i being provided with an enlarged head 22 and the other end being provided with an aperture for receiving the hasp of a padlock or seal 26.

With the guard member and the locking bar thus assembled on the face plate i2, it will be apparent that the operating lever i6 is locked against movement between its operating positions, and thus accidental or inadvertent operatiori of the lever i6 is prevented. At the same time, howeven'operation of the lever i6 may be accomplished in an emergency simply by withdrawing the screws 119 so as to permit bodily.

, removal of the guard from the face plate i2.

After the operating lever has been moved to the desired position, the guard may be replaced and the screws reinserted so as to retain the guard in its proper locking position.

As stated above, it is sometimes desirable to render the switch entirely tamper-proof; that is, to prevent operation of the switch under all conditions except upon removal of the padlock or seal 24. For this purpose I provide a hood-shaped cover 25 arranged telescopically to enclose the channel-like guard so as to render the detachable means or screws 89 inaccessible. This cover member 25 is preferably hingedly connected to one end of the guard member by means of a hinged plate 2E'which is secured to one of the yoke members I8 by the associated screw as and which is provided with hinge fingers 27 which extend outwardly beyond the end of the yoke member I8 and then inwardly to the face plate I2.

These hinged fingers extend through suitable apertures 28 in one end of the hood-shaped cover 25 so as hingedly to mount the cover for movement between the closed position shown in heavy guard may be removed from the face plate 2 for.

emergency operation of the lever 16, as described above. When the cover member 25 is in its closed position, however, these screws i9 are inaccessible and the switch may then beoperated only upon removal of the padlock 24 and the locking bar 26 Furthermore, since the cover or face plate I2 is secured to the casing II by the screws i9, it will be apparent that when the hood 25 is locked into closed position the circuit breaker terminals and the wiring connections (not shown) within the casing II are also inaccessible except upon removal of the padlock 24. Thus the'hood 25 not only prevents tampering with the operating lever IE, but also prevents tampering with the positions, the combination of channel-like guard 'member substantially U-shaped in cross-section and comprising parallel side walls connected adjacent their respective opposite ends by spaced yoke members, detachable means for securing said yoke members to said face plate in face-toface relation therewith so that said operating lever extends into the space between said yoke members and so .that said side walls extend substantially parallel to the path of movement of said operating lever, a locking bar disposed in alined apertures in said side walls and extending across said channel in the path of movement of saidoperating lever, sealing means for preventing unauthorized removal of said locking bar, said guard member and said locking bar thereby preventing operation of said lever between said operating positions, and a hoodshaped cover member for entirely enclosing said guard to render said detachable means inaccessible, said cover member having apertures in the side walls thereof through which said locking bar extends whereby said switch is rendered entirely tamper-proof, said operating lever being accessible for operation. only upon removal of said sealing means.

2. In an electric switch having-a face plate and an operating lever extending therethrough for movement between a plurality of operating positions, the combination of a channel-like guard member substantially U-shaped in cross-section and comprising parallel side walls connected adjacent their respective opposite ends by spaced yoke members, detachable means for securing said yoke members to said face plate in face-to face relation therewith so that said operating lever extends into the space between said yoke members and so that said side walls extend substantially parallel to the path of movement of said operating lever, a locking bar disposed in alined apertures in said side walls and extending across said channel in the path of movement of said operating lever, sealing means for preventing unauthorized removal of said locking barfsaid guard member and said locking bar thereby preventing operation of said lever between said operating positions, and a hood-shaped cover member hingedly connected to said guard member for movement between open and closed position, said cover member when closed entirely housing said guard member to render said detachable means inaccessible, said cover member having apertures in the side walls thereof adapted to receive said locking bar to lock said cover in said closed position whereby said switch is rendered entirely tamper-proof, said operating lever being accessible for operation removal of said sealing means.-

3. In an electric switch having'a face plate and an operating lever extending therethrough for movement between a plurality of operating positions, the combination of a channel-like guard only upon member substantially U-shaped in cross-section and comprising parallel side walls connected adjacent their respective opposite ends by spaced yoke members, detachable means for securing said yoke members to said face plate in face-to-face relation therewith so that said operating lever extends into the space between said yoke members and so that said side walls extend substantially parallel to the path of movement of said operating lever, a locking bar disposed in alined apertures in said side walls and extending across said channel in the path of movement of said operating lever, sealing means for preventing unauthorized removal of said locking ban-said guard member and said locking bar thereby preventing operation of said lever between said operating positions, a hinge plate secured to one of said yoke members by saiddeta'chable means, said hinge plate including a hinge-finger extending outwardly from said yoke member and inwardly to said face plate, and a hood-shaped cover member having an aperture in one end thereof cooperating with said hinge finger hingedly to mount said cover on said guard'member for movement between open and closed positions, said cover member when closed entirely housing said guard member to render said detachable :means inaccessible, said cover member having alined apertures in the side walls thereof for receiving said locking bar, whereby said cover may be locked in said closed position to render said switch entirely tamper-proof, said operating lever then being accessible for operation only upon removal of said sealing means and said locking bar.

4. In an electric switch having a face plate and an operating lever extending through an aperture in the face plate for movement between a plurality ofoperating positions, the combination of a guard member for said operating lever provided with'side walls on opposite sides of said lever, detachable means for securing said guard member to said face plate with said side walls extending substantially parallel with the path of movement of said operating lever, said detachable securing means requiring a tool for manipulation thereof to attach or detach said guard member, and said side walls being provided with apertures oppositely disposed with respect to each other, an enclosing member covering said detachable means and provided with apertures aligned with the apertures in said side walls, a bar disposed in said apertures in the path of movement of said operating lever, and locking means for preventing ready removal of said bar.

FRED G. von HooRN. 

